1. Field of the Invention
The present invention generally relates to an improved comfort device to be used with a nasal mask. In particular, the device is useful in combination with masks which are used for the treatment of respiratory conditions and assisted respiration. The invention assists in fitting the mask to the face as well.
2. General Background
Nasal masks are commonly used in the treatment of respiratory conditions and sleep disorders by delivering a flow of breathable gas to a patient to either assist the patient in respiration or to provide a therapeutic form of gas to the patient to treat sleep disorders such as obstructive sleep apnea. These nasal masks typically receive a gas through a supply line which delivers gas into a chamber formed by walls of the mask. The mask is generally a semi-rigid mask which has a face portion which covers at least the wearer's nostrils. Additionally, the mask may be a full face mask. The mask is normally secured to the wearer's head by straps. The straps are adjusted to pull the mask against the face with sufficient force to achieve a gas tight seal between the mask and the wearer's face. Gas is thus delivered to the mask and the wearer's nasal passages and/or mouth.
One of the problems that arises with the use of the mask is that in order for the straps to be tight, the mask is compressed against the wearer's face and may push unduly hard on the wearer's nose. Additionally, the mask may move around on the wearer's face. Thus, there has been provided a forehead support, which provides a support mechanism between the mask and the forehead. This forehead support prevents both the mask from pushing too strongly against the wearer's nose and/or facial region as well as minimize movement of the mask with the addition of a contact point between the mask and the wearer's head as well as minimize uncomfortable pressure points of the mask. Additionally, the forehead support may prevent the airflow tube from contacting the wearer's forehead or face.
FIG. 1 shows a general perspective view of a related art forehead support 10. The forehead rest or support 10 is attached to an airflow tube 12 extending from the mask 14. The mask 14 and forehead support 10 are shown with headgear 16 which secures the mask 14 to the head of a patient. As can be seen in FIG. 1, the headgear 16 loops through the forehead support 10 at loops 18 and 20. This pulls the forehead support 10 against the forehead, thus creating a snugly fitted mask 14 and also provides a stabilizing member for the mask 14.
FIG. 2 discloses the construction of the related art forehead support 10. The forehead support 10 has pads 24 and 26, a back side of which can be seen in greater detail in FIG. 10. These pads 24 and 26 are the actual contact points of the forehead support 10 to the forehead. The support pads 24 and 26 are mounted to the bridge 32. Arms 34 and 36 are secured to bridge 32 by an adjustable locking mechanism which is better illustrated in the figures below. The bridge 32 provides three purposes to the forehead support 10. First, it acts as a securing means for pads 24 and 26. Second, it has loops 18 and 20 which receive the optional headgear 16 shown in FIG. 1. Finally, it receives arms 34 and 36, which may be adjusted, as described below. The bridge 32 and arms 34 and 36 operate in a cantilever fashion and are made of a polymeric material, which may be easily molded. Additionally, arms 34 and 36 join together to create an annular space 38 to receive airflow tube 12 which is connected to a flow generator to generate breathable air or some type of therapeutic gas. Arms 34 and 36 create an operational hinge. The tube 12 is an axis of this hinge.
FIG. 3 is an exploded view of FIG. 2 and shows the forehead support 10 in greater detail. Bridge engaging pins 56, 58, 60 and 62 are shown in FIG. 3. As will be more apparent in the figures below, these engaging pins provide for the adjustability of the forehead support 10. Bridge 32 includes slots 76, 78, 82, 84, 86, 88 and 90 (see FIG. 9) and a mirror set of slots on the upper portion of bridge 32 (not visible in FIG. 9) for selectively receiving pins 56, 58, 60 and 62. These slots open to the forehead side of the bridge. Additionally, there is a space or recess at arms 34 and 36 shown on arm 34 as 64. The purpose of this space 64 is so that the user may compress arm 34 and thus press pins 56 and 58 together by pressing on surfaces 66 and 68. The purpose of the compression is to decrease the distance between pins 56 and 58 such that they may be selectively inserted and locked into the desired pair of slots on bridge 32. The length of the pins 56 and 58 is such that even when the pins are pressed together, they do not clear the slots in the bridge sufficiently to allow the arms to be disassembled from the bridge without further action.
FIG. 4 is a side view of the mask 14 and forehead support 10. The mask is shown as 14 with a dotted line showing the nose of a wearer 70 and the dotted line showing the forehead 72 of the wearer. Pad 26 is shown compressed by the forehead of the individual wearing the mask.
FIG. 5 is a top view of the forehead support 10 taken along lines 5 of FIG. 4. Also, the mask 14 is not shown in FIG. 5. This figure illustrates the forehead support 10 in a position wherein the forehead support is in the closest position to the tube 12 (shown as merely a space in FIGS. 5-6). The bridge 32 is shown essentially in contact with tube 12. The pins 56, 58, 60 and 62 are shown in their furthest position from the center of the bridge 32, engaging slot pairs 88 and 90. This position may be utilized by someone with a large, protruding or bulbous forehead, or a high nasal bridge, or someone who prefers the airflow tube to be snug against their forehead. FIG. 6 shows the same forehead support in the next position, wherein the bridge 32 is moved away from tube 12 such that there is a gap 74 between bridge 32 and tube 12. Here, pins 56, 58, 60 and 62 engage slot pairs 76 and 86. As is visible from the figure, the forehead support 10 is now moved away from tube 12, and is positioned differently than in FIG. 5. This may be configured to fit someone with a less protruding forehead, or someone who wants the flexible tube further from their head than is possible in FIG. 5. FIGS. 7 and 8 show the third and fourth position for the forehead support.
The related art arm 34 is shown in greater detail in FIGS. 11-13. As can be seen in the top view of the arm 34 shown in FIG. 11, the arm 34 includes a semicircular portion 100, on an interior of which the annular space 38 is situated. An extending portion 102 extends from the semicircular portion 100. Surfaces 66 and 68, space 64 and engaging pins 56 and 58 are positioned on the extending portion 102. Each surface 66 and 68 includes a generally oval depression 106 and 108, respectively, positioned near the pins 56 and 58. These oval depressions 106 and 108 can be felt by the wearer of the mask and assist the wearer in properly positioning his or her fingers near the pins 56 and 58 when it is desired to adjust the forehead support. This is especially important when the mask and forehead support are positioned on the wearer's head because at such time, the wearer cannot easily see where to place his or her fingers to adjust the forehead support. The oval depressions not only assist the wearer in properly positioning his or her fingers for adjusting the support, by virtue of the fingers engaging the depressions, the depressions also help maintain the fingers in the appropriate position.
FIG. 12 is a side view of the arm shown in FIG. 11. As can be seen there, the semicircular portion 100 only extends upward to half of the height of the arm 34. Because of this, the arm 34 is reversible, i.e., it can be flipped over, and then can be used as arm 36. Thus, only one arm design need be molded and this can be used as both arm 34 and arm 36, depending on its orientation. Extending portion 102 includes two horizontal flanges 110 and 112 connected by an intermediate web 114. The two horizontal flanges are thicker in the horizontal direction and thinner in the vertical direction than web 114. The space 64 is positioned on web 114. The force required to press the pins 56 and 58 together is a function of the amount of material of the extending portion 102 on either side of the space 64 in the vertical direction, the length space 64 extends along portion 102 (i.e., the length of each cantilever arm on either side of space 64) and the type of material from which the arm 34 is constructed. These arms have been constructed of a polycarbonate, specifically, Makrolon 2458 manufactured by Bayer.
FIG. 13 shows a cross-section of the arm 34 along line 13—13 in FIG. 12. The comparative thicknesses of the flange 112 and the web 114 in the horizontal direction can best be seen here. The hatched portion of the arm 34 is the portion of the web 114 beyond the extended length of the space 64.
It has been found that while the related art forehead support performs correctly if operated according to the instructions, an improvement can be made to reduce the risk of breakage when the forehead support is operated in a manner contrary to instructions.
Further, because depressions 106 and 108 are relatively narrow, an improvement can be made to allow the user to positively and firmly position his or her fingers to press the pins 56 and 58 together. Finally, because there is a relatively large amount of material contact between an interior of semicircular portion 100 and an exterior of airflow tube 12, this can result in a relatively large amount of friction between the arm 34 and the tube 12, thereby requiring additional force to pivot the arm 34 around the tube 12 for adjustment purposes.